[Cob] mold or fungus?

[Tys Sniffen]

Hey all,

As we keep cobbing here in Northern California into the winter, I see some
strange white mold or fungus patches showing up, generally on the inside of
our walls.  That seems pretty odd to me, but of course, here in the woods a
wispy white spider-web-like mat of mold is not uncommon.  

This is on the cob wall itself, right about where the wet part meets the dry
layers from batches past. 

Any thoughts on this? We're thinking of going around with a spray bottle
with bleach-y water in it, but I'm also thinking that a couple plaster
layers will take care of this... but I don't want mushrooms popping out of
my walls later on.

Tys